feat: Add `gitlab` icon

Closes #119

icons/gitlab.svg

+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24"><path d="M22.65,14.39,12,22.13,1.35,14.39a.84.84,0,0,1-.3-.94L2.27,9.67,4.71,2.16A.42.42,0,0,1,4.82,2,.43.43,0,0,1,5.4,2a.42.42,0,0,1,.11.18L7.95,9.67h8.1l2.44-7.51A.42.42,0,0,1,18.6,2a.43.43,0,0,1,.58,0,.42.42,0,0,1,.11.18l2.44,7.51L23,13.45A.84.84,0,0,1,22.65,14.39Z" fill="none" stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"/></svg>
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